This invention relates to metal structures wherein horizontal members are supported upon posts at different vertical levels, and more particularly to storage installations wherein a horizontal beam is adjustably supported at a desired vertical level by the entry of tab or lug means carried by the beam into openings spaced vertically along the posts.
Many metal framework structures have been developed which basically employ vertical columns or posts that are interconnected by horizontal members or beams which can be adjustably positioned at different vertical levels on the posts. In storage installations, these horizontal beams generally, either directly or indirectly, support the load which the framework carries and transfer it to the posts. For example, in some storage rack installations, e.g. certain types of pallet racks, the load may be supported directly upon horizontal beams; whereas in other installations, shelves or decking is supported from opposite horizontal beams. The field of adjustable storage racks has, in the past 15 years or so, become highly sophisticated and versatile in its design so as to accommodate the storage of almost any type of merchandise. A particularly efficient design for metal shelving has recently been developed and is depicted in U.S. patent application Ser. No. 831,524, filed Sept. 8, 1977. This design utilizes posts having spaced pairs of parallel vertical slots which accommodate connectors formed at the ends of the horizontal beams. The beams, in turn, include lips for the support of individual metal shelves, and the design is such that the entire assembly can be accomplished without the use of nuts and bolts.
In the above-described shelving system, as well as in pallet racks, it is important that, once installed, the beams do not become inadvertently detached, which is consideration that grows out of the fact that such framework is designed to be capable of easy and simple erection. As a result, a number of different latching or locking arrangements have been developed, a few examples of which are depicted in U.S. Pat. Nos. 3,637,087, 3,626,487, 3,303,937, 3,144,944, 3,070,237 and 3,042,221. None of these arrangements is considered to be totally satisfactory, and none has been truly applicable to a number of different structural connections of this general type.